This invention relates to rotary lawn mowers and the like, and more particularly, to a replaceable cutting edge for lawn mower blades and the like.
Currently, when the blades of a rotary lawn mower become dull or worn, it is necessary to remove and replace the entire blade body with a new blade. Sometimes the blade can be sharpened while it is still attached to the lawn mower engine shaft, however, the latter is difficult as it requires lifting the mower and there is a risk of cutting oneself as the entire lawn mower blade has to be replaced, there is a high cost in terms of labor and material, especially for landscaping companies, which may be required to do so on at least a daily basis.
Thus, there exists a need for a lawn mower blade with a cutting edge that can be easily replaceable without having to replace the entire lawn mower blade body.
The prior patented art includes many replaceable cutting edges for lawn mower blades, but none just like the present invention. The prior patented art includes the following:
______________________________________ U.S. Pat. No. Inventor Issue Date ______________________________________ 5,018,347 Feilen May 28, 1991 5,036,654 Malutich Aug. 6, 1991 4,779,407 Pattee Oct. 25, 1988 4,445,315 Roszkowski May 1, 1984 3,769,784 Jones Nov. 6, 1973 3,097,468 Johnson July 16, 1963 4,471,603 Veltin Jr. Sept. 18, 1984 3,514,935 Bonsor June 2, 1970 3,327,460 Blackstone June 27, 1967 2,932,147 Beeston, Jr. April 12, 1960 3,563,015 Renfroe Feb. 16, 1971 3,665,692 Hughes May 30, 1972 4,651,510 Malutich March 24, 1987 4,375,148 Beck March 1, 1983 ______________________________________
The Feilen patent teaches a removable cutting edge that requires an entirely new blade with a cut, the forwarding rotating surfaces of the blade into which the cutting edge is inserted. In Feilen, the cut destroys the structural integrity of the blade. The Malutich patent teaches a different replaceable cutting edge that is secured by clips to a lawn mower blade. The Pattee patent shows another replaceable cutting edge that is attached by inserting a retaining arm on the blade into a slot in the cutting edge. The Roszkowski patent teaches yet another replaceable cutting edge that snaps onto the blade and emits an audible tone if the cutting edge is not installed correctly. The Jones patent shows another removable cutting blade in which the cutting edges are attached to the blade by a nut and bolt. The Johnson patent teaches replaceable cutting edges that slide into the blade and use a disk on the inner end to keep the blade in place against the centrifugal force caused by blade rotation. The Veltin, Jr. patent teaches another removable cutting edge for lawn mower blades which uses two bands to hold the edges to the blade. The Bonsor patent teaches another removable cutting edge which is held to the blade by nuts and bolts. The Blackstone patent shows removable cutting edges using rivets and a bolt/nut combination to hold it to the blade. The Beeston, Jr. patent teaches other removable cutting edges held on by rivets that slide into a slot on the blade. The Renfroe patent shows removable cutting edges that slide into channels at the end of the blades. The Hughes patent shows another removable cutting edge which is held on by nuts and bolts. The second Malutich patent teaches removable cutting edges which fit into specially designed mower blades. Finally, the Beck patent shows yet other removable cutting edge that is attached to the blade by insertion into a wedged slot on the blade.
Contrary to the above referenced prior patented art, the present invention allows the use of a fairly standard lawn mower blade which merely has a series of grooves and steps machined onto the forward cutting surfaces of the blades. The removable cutting edges contain a channel with matching grooves and steps which allows the edges to be easily and quickly slided onto the blades. As the present invention does not require a cut into the edges of the blades or snaps, nuts or bolts, the structural integrity and aerodynamic properties of the lawn mower blade are maintained.